The religion of Islam was officially began in 610 A.D., This happens when angel Gabriel visited Muhammad while on retreat in a cave near Mecca. The angel recites to him the first revelations of the Qur’an and inform him that he was the God’s prophet. Later, Muhammad was told to call his people to worship one God, but they react with hostility and begin to persecute him and his followers. Muhammad and his followers migrate to the nearby town Yathrib (later to be know as Medina), where the people accepted Islam. This marks the ""hijrah"" or ""emigration,"" and the beginning of the Islamic calendar. In Medina, Muhammad establishes an Islamic state based on the laws revealed in the Quran and the inspired guidance coming to him from God. Muhammad and his followers starts to spread the teachings of Islam throughout the Arabian peninsula. As he returns to Mecca with a large number of his followers. He enter the city peacefully, and eventually all its citizens accept Islam. The prophet clears the idols and images out of the Kaaba and rededicates it to the worship of God alone. Muhammad began writing down everything he had learned from God and recorded it in a book called the Qur'an. This book has been translated and passed down over the centuries, but only books translated in the original Arabic language are considered to be authentic.